title: Recruitment of a species-specific translational arrest module to monitor different cellular processes.
abstract: Nascent chain-mediated translation arrest serves as a mechanism of gene regulation. A class of regulatory nascent polypeptides undergoes elongation arrest in manners controlled by the dynamic behavior of the growing chain; Escherichia coli SecM monitors the Sec protein export pathway and Bacillus subtilis MifM monitors the YidC membrane protein integration/folding pathway. We show that MifM and SecM interact with the ribosome in a species-specific manner to stall only the ribosome from the homologous species. Despite this specificity, MifM is not exclusively designed to monitor membrane protein integration because it can be converted into a secretion monitor by replacing the N-terminal transmembrane sequence with a secretion signal sequence. These results show that a regulatory nascent chain is composed of two modular elements, one devoted to elongation arrest and another devoted to subcellular targeting, and they imply that physical pulling force generated by the latter triggers release of the arrest executed by the former. The combinatorial nature may assure common occurrence of nascent chain-mediated regulation.
authors.affiliation: Faculty of Life Sciences, Kyoto Sangyo University, Motoyama, Kamigamo, Kita-Ku, Kyoto 603-8555, Japan.
authors.forename: Shinobu
authors.initials: S
authors.lastname: Chiba
authors.forename: Takashi
authors.initials: T
authors.lastname: Kanamori
authors.forename: Takuya
authors.initials: T
authors.lastname: Ueda
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Akiyama
authors.forename: Kit
authors.initials: K
authors.lastname: Pogliano
authors.forename: Koreaki
authors.initials: K
authors.lastname: Ito
mesh_terms: D001412:Bacillus subtilis / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000378:metabolism*; D005786:Gene Expression Regulation; D014176:Protein Biosynthesis / Q000235:genetics*; D012270:Ribosomes / Q000378:metabolism*; D013045:Species Specificity; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D029968:Escherichia coli Proteins; C497347:SecM protein, E coli; D014157:Transcription Factors